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from __future__ import annotations |
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import sys |
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from abc import ABCMeta, abstractmethod |
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from collections.abc import Awaitable, Callable |
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from types import TracebackType |
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from typing import TYPE_CHECKING, Any, Protocol, TypeVar, overload |
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if sys.version_info >= (3, 11): |
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from typing import TypeVarTuple, Unpack |
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else: |
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from typing_extensions import TypeVarTuple, Unpack |
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if TYPE_CHECKING: |
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from .._core._tasks import CancelScope |
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T_Retval = TypeVar("T_Retval") |
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T_contra = TypeVar("T_contra", contravariant=True) |
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PosArgsT = TypeVarTuple("PosArgsT") |
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class TaskStatus(Protocol[T_contra]): |
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@overload |
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def started(self: TaskStatus[None]) -> None: |
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... |
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@overload |
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def started(self, value: T_contra) -> None: |
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... |
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def started(self, value: T_contra | None = None) -> None: |
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""" |
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Signal that the task has started. |
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:param value: object passed back to the starter of the task |
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""" |
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class TaskGroup(metaclass=ABCMeta): |
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""" |
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Groups several asynchronous tasks together. |
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:ivar cancel_scope: the cancel scope inherited by all child tasks |
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:vartype cancel_scope: CancelScope |
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""" |
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cancel_scope: CancelScope |
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@abstractmethod |
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def start_soon( |
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self, |
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func: Callable[[Unpack[PosArgsT]], Awaitable[Any]], |
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*args: Unpack[PosArgsT], |
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name: object = None, |
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) -> None: |
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""" |
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Start a new task in this task group. |
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:param func: a coroutine function |
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:param args: positional arguments to call the function with |
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:param name: name of the task, for the purposes of introspection and debugging |
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.. versionadded:: 3.0 |
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""" |
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@abstractmethod |
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async def start( |
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self, |
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func: Callable[..., Awaitable[Any]], |
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*args: object, |
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name: object = None, |
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) -> Any: |
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""" |
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Start a new task and wait until it signals for readiness. |
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:param func: a coroutine function |
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:param args: positional arguments to call the function with |
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:param name: name of the task, for the purposes of introspection and debugging |
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:return: the value passed to ``task_status.started()`` |
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:raises RuntimeError: if the task finishes without calling |
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``task_status.started()`` |
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.. versionadded:: 3.0 |
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""" |
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@abstractmethod |
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async def __aenter__(self) -> TaskGroup: |
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"""Enter the task group context and allow starting new tasks.""" |
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@abstractmethod |
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async def __aexit__( |
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self, |
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exc_type: type[BaseException] | None, |
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exc_val: BaseException | None, |
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exc_tb: TracebackType | None, |
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) -> bool | None: |
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"""Exit the task group context waiting for all tasks to finish.""" |
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